Radiation sensitive composition

ABSTRACT

A radiation sensitive composition comprising (A), a mixture of an isoindolinone pigment and a yellow organic pigment, (B) an alkali-soluble resin, (C) a polyfunctional monomer and (D) a photopolymerization initiator. The composition is useful for production of an additive or subtractive color filter which is used in a reflection-type color liquid crystal display device.

This is a Division of application Ser. No. 09/120,883, filed Jul. 23,1998, U.S. Pat. No. 6,140,019.

DETAILED DESCRIPTION OF THE INVENTION

The present invention relates to a radiation sensitive compositioncontaining a specific pigment. More specifically, it relates to aradiation sensitive composition which can be advantageously used for theproduction of an additive or subtractive color filter to be used in areflection-type color liquid crystal, display device.

In color filters used in a color liquid crystal display device, two ormore different color pixels are arranged in parallel to one another oracross one another to form a striped pixel pattern, or in bothhorizontal and transverse directions to form a square pixel pattern onthe surface of a transparent substrate such as glass. The pixel is asminuscule as several tens to several hundreds of micrometers.

To produce a color filter having such minuscule pixels arrangedregularly, there have been employed a dying method in which a coatingfilm formed by coating a photosensitive resin on a substrate is exposedto radiation through a photomask to cure exposed portions and developed,and after unexposed portions are removed to form a pattern, the patternis dyed; a photolithography method in which a coating film is formedusing a composition comprising a photosensitive resin and a colorant(dye or pigment) dispersed or dispersed therein, exposed and developedin the same manner as in the dying method to form a pattern; and thelike.

In a color liquid crystal display device, a transparent electrode madefrom indium oxide, tin oxide or the like is formed on a color filter byvapor deposition or sputtering and an alignment layer for aligningliquid crystals in a fixed direction is further formed on thetransparent electrode so as to drive the liquid crystals. To obtain ahigh-performance transparent electrode and alignment layer, a hightemperature of 200° C. or higher, preferably 250° C. or higher isrequired when these are formed.

Of color filters manufactured by the above methods, a color filterproduced by using a dye has high transparency to radiation but isinsufficient in terms of heat resistance. Therefore, this method has aproblem in that the formation of a transparent electrode and analignment layer must be carried out at a temperature lower than 200° C.,thereby making it impossible to ensure sufficient performance for thetransparent electrode and alignment layer. A color filter produced byusing a dye is also inferior in light resistance and hence not suitablefor outdoor use.

Then, a pigment has recently been used in place of a dye, and most ofcolor filters currently manufactured comprise an organic pigment.

Color liquid crystal display devices are roughly divided intotransmission-type color liquid crystal display devices which displayimages with transmission light from a backlight installed at the back ofthe device and reflection-type color liquid crystal display deviceswhich display images by reflecting incident light coming from the frontof the device with a reflector such as an aluminum foil provided on thereverse of a transparent substrate installed at the back of the device.The reflection-type color liquid crystal display devices have beenwidely used because they have such an advantage that another separatelight source is not required and power consumption is low.

Color filters to be used in color liquid crystal display devices areavailable in additive color filters having three primary colors—red (R),green (G) and blue (B)—and subtractive color filters having three colorscomplementary to the primary colors—cyan (C), magenta (M) and yellow(Y).

JP-A 9-68608 (the term “JP-A” as used herein means an “unexaminedpublished Japanese patent application”) discloses that a color filterhaving excellent heat resistance and light resistance and color purityequal to or higher than that of a color filter produced by the dyeingmethod can be formed by using a specific azo metal salt pigment or amixture of the pigment and a yellow pigment as a colorant for a coloringcomposition for use in a reflection-type color liquid crystal displaydevice.

However, since the relationship between the spectral transmittance ofthe colorant used and the spectrum of surrounding light (such assunlight and fluorescent light) is not taken into consideration in thiscoloring composition and the coloring composition is inferior in whitebalance, the composition is still unsatisfactory as a coloringcomposition used for the formation of a color filter for areflection-type color liquid crystal display device.

Therefore, the development of an additive color filter to be used in areflection-type color liquid crystal display device which has heatresistance, light resistance and spectral transmittance optimized basedon the spectrum of surrounding light as well as a subtractive colorfilter to be used in a reflection-type color liquid crystal displaydevice which has heat resistance, light resistance and excellent whitebalance has been strongly desired.

It is therefore an object of the present invention to provide aradiation sensitive composition containing a specific pigment.

It is another object of the present invention to provide a radiationsensitive composition which is advantageously used for the production ofan additive and/or subtractive color filter having excellent heatresistance and light resistance and spectral transmittance optimized tosuit the spectrum of surrounding light.

It is still another object of the present invention to provide aradiation sensitive composition which is advantageously used for theproduction of a subtractive color filter having excellent heatresistance, light resistance and white balance.

It is still another object of the present invention to provide aradiation sensitive composition which is advantageously used for theproduction of the above color filters to be used in a reflection colorliquid crystal display.

Other objects and advantages of the present invention will becomeapparent from the following description.

According to the present invention, firstly, the above objects andadvantages of the present invention can be attained by a radiationsensitive composition (may be referred to as “the first radiationsensitive composition of the present invention” hereinafter) comprising:

(A1) a colorant containing a quinacridone pigment represented by thefollowing formula (1):

 wherein R¹ to R⁸ are independently a hydrogen atom, a methyl group or achlorine atom;

(B) an alkali-soluble resin;

(C) a polyfunctional monomer; and

(D) a photopolymerization initiator.

Secondly, the above objects and advantages of the present invention canbe attained by a radiation sensitive composition (may be referred to as“the second radiation sensitive composition of the present invention”hereinafter) comprising:

(A2) a colorant containing a mixture of an isoindolinone pigmentrepresented by the following formula (2) and a yellow organic pigment;

(B) an alkali-soluble resin;

(C) a polyfunctional monomer; and

(D) a photopolymerization initiator.

Thirdly, the above objects and advantages of the present invention canbe attained by a radiation sensitive composition (may be referred to as“the third radiation sensitive composition of the present invention”hereinafter) comprising:

(A3) a colorant containing copper phthalocyanine blue represented by thefollowing formula (3):

 at least either one of a green pigment represented by the followingformula (4):

 and a green pigment represented by the following formula (5):

 in an amount of 50 wt % or less, based on the total weight of thecopper phthalocyanine blue and the green pigments;

(B) an alkali-soluble resin;

(C) a polyfunctional monomer; and

(D) a photopolymerization initiator.

The term “radiation” as used in the present invention includes visiblelight, ultraviolet light, far ultraviolet light, X-ray, electron beamand the like.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows the measurement result of the spectral transmittance of acolor filter produced using the radiation sensitive composition(composition 1) of the present invention;

FIG. 2 shows the measurement result of the spectral transmittance of acolor filter produced using a comparative radiation sensitivecomposition (Comparative Example 1);

FIG. 3 shows the measurement result of the spectral transmittance of acolor filter produced using another comparative radiation sensitivecomposition (Comparative Example 2);

FIG. 4 shows the measurement results of the spectral transmittance of acolor filter produced using the radiation sensitive composition of thepresent invention (composition 2) and a color filter produced using acomparative radiation sensitive composition;

FIG. 5 shows the measurement result of the spectral transmittance of acolor filter produced using the radiation sensitive composition of thepresent invention (composition 3);

FIG. 6 shows the measurement result of the spectral transmittance ofanother color filter produced using the radiation sensitive compositionof the present invention (composition 4);

FIG. 7 shows the measurement result of the spectral transmittance of acolor filter produced using a comparative radiation sensitivecomposition (Comparative Example 4);

FIG. 8 shows the simulation result of the white balance of a colorfilter produced using the radiation sensitive composition of the presentinvention (composition 5); and

FIG. 9 shows the simulation result of the white balance of a colorfilter produced using a comparative radiation sensitive composition.

The present invention will be described in detail below.

(A) Colorant

The first, second and third radiation sensitive compositions of thepresent invention contain a colorant comprising a quinacridone pigmentof the above formula (1), a mixture of an isoindolinone pigment of theabove formula (2) and other yellow pigment, and a mixture of the copperphthalocyanine blue of the above formula (3) and at least either one ofthe green pigment of the above formula (4) and the green pigment of theabove formula (5), respectively.

Illustrative examples of the quinacridone pigment (to be referred to as“quinacridone pigment (1)” hereinafter) are indicated by the followingColor Index (C.I.; issued by The Society of Dyers and Colourists)numbers and component names (within the parentheses): C.I. PigmentViolet 19 (quinacridone), C.I. Pigment Red 122(2,9-dimethylquinacridone), C.I. Pigment Red 202(2,9-dichloroquinacridone), C.I. Pigment Red 206 (solid solution ofquinacridone and 6,13-dioxoquinacridone), C.I. Pigment Red 207 (solidsolution of quinacridone and 4,11-dichloroquinacridone) and C.I. PigmentRed 209 (3,10-dichloroquinacridone). The quinacridone is available inα-, β- (violet) and γ- (red) type crystal forms. Particularly preferredas the quinacridone pigment (1) in the present invention is γ-typequinacridone.

The first radiation sensitive composition can contain other pigment incombination with the quinacridone pigment (1) as a colorant component inan amount not impairing the desired effect of the present invention.

Although the above other pigment can be suitably selected according tothe application of a color filter and the desired color of a pixel, anorange pigment is preferred because the hue of the pixel can be easilycontrolled with the orange pigment.

Illustrative examples of the above orange pigment include thoserepresented by such color index (C.I.) numbers as C.I. Pigment Orange36, C.I. Pigment Orange 64, C.I. Pigment Orange 71 and the like. Ofthese, C.I,. Pigment Orange 71 is particularly preferred.

The colorant contained in the first radiation sensitive composition isparticularly preferably a mixture of a quinacridone pigment (1) and anorange pigment. The proportion of the orange pigment therein isgenerally 40 wt % or less, preferably 35 wt % or less, more preferably 5to 30 wt %, based on the total weight of all pigments.

The second radiation sensitive composition contains a colorantcomprising a mixture of an isoindolinone pigment represented by theabove formula (2) and a yellow organic pigment.

The isoindolinone pigment represented by the above formula (2)corresponds to C.I. Pigment Yellow 110 according to color index (C.I.;issued by The Society of Dyers and Colourists) number. The yelloworganic pigment is used to control the hue of the obtained pixel.

Illustrative examples of the yellow organic pigment are represented bythe following color index numbers: C.I, Pigment Yellow 1, C.I. PigmentYellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13, C.I. PigmentYellow 14, C.I. Pigment Yellow 16, C.I. Pigment Yellow 17, C.I. PigmentYellow 20, C.I. Pigment Yellow 24, C.I. Pigment Yellow 31, C.I. PigmentYellow 55, C.I. Pigment Yellow 60, C.I. Pigment Yellow 65, C.I. PigmentYellow 73, C.I. Pigment Yellow 74, C.I. Pigment Yellow 81, C.I. PigmentYellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow 95, C.I. PigmentYellow 97, C.I. Pigment Yellow 98, C.I. Pigment Yellow 100, C.I. PigmentYellow 101, C.I. Pigment Yellow 104, C.I. Pigment Yellow 106, C.I.Pigment Yellow 108, C.I. Pigment Yellow 109, C.I. Pigment Yellow 113,C.I. Pigment Yellow 114, C.I. Pigment Yellow 116, C.I. Pigment Yellow117, C.I. Pigment Yellow 119, C.I. Pigment Yellow 120, C.I. PigmentYellow 126, C.I. Pigment Yellow 127, C.I. Pigment Yellow 128, C.I.Pigment Yellow 129, C.I. Pigment Yellow 138, C.I. Pigment Yellow 139,C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I. Pigment Yellow152, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154, C.I. PigmentYellow 155, C.I. Pigment Yellow 156, C.I. Pigment Yellow 166, C.I.Pigment Yellow 168, C.I. Pigment Yellow 175 and the like.

The yellow organic pigment listed above may be used alone or incombination of two or more. The proportion of the yellow organic pigmentused is preferably 25 wt % or less, more preferably 5 to 25 wt %,particularly preferably 10 to 20 wt % of the total weight of allpigments.

The third radiation sensitive composition contains a colorant comprisinga mixture of the copper phthalocyanine blue of the above formula (3) andat least either one of the green pigment of the above formula (4) andthe green pigment of the above formula (5). The content of the greenpigment is 50 wt % or less, based on the total weight of the copperphthalocyanine blue and the green pigment.

The copper phthalocyanine blue of the above formula (3) is preferablyβ-type crystalline copper phthalocyanine blue or non-crystalline andnon-cohesive copper phthalocyanine blue.

The β-type crystalline copper phthalocyanine blue corresponds to C.I.Pigment Blue 15:3 according to color index (C.I.: issued by The Societyof Dyers and Colourists) number and the non-crystalline and non-cohesivecopper phthalocyanine blue corresponds to C.I. Pigment Blue 15:4according to color index (C.I.) number. Of these, C.I. Pigment Blue 15:4is particularly preferred.

The green pigment is used to control the hue of the obtained pixel.

The green pigment represented by the above formula (4) corresponds toC.I. Pigment Green 7 according to color index (C.I.) number and thegreen pigment represented by the above formula (5) corresponds to C.I.Pigment Green 36 according to color index (C.I.) number. Of these, C.I.Pigment Green 36 is particularly preferred.

The proportion of the green pigment used is 50 wt % or less, preferably50 to 10 wt %, more preferably 50 to 25 wt %, based on the total weightof all pigments, as described above.

The first radiation sensitive composition is advantageously used for theproduction of additive color filter and subtractive color filter to beused in a reflective-type color liquid crystal display device. Thesecond and third radiation sensitive compositions can be advantageouslyused for the production of a subtractive color filter.

In the present invention, the surface of each pigment may be modifiedwith a polymer. The polymer for modifying the surface of a pigment is,for example, a polymer disclosed by JP-A 8-259876 or a variety ofcommercial polymers or oligomers for dispersing a pigment.

The pigments used in the present invention can be used in conjunctionwith a dispersant as desired.

The dispersant is, for example, a cationic, anionic, nonionic,amphoteric, silicone-based or fluorine-based surfactant.

Illustrative examples of the surfactant include polyoxyethylene alkylethers such as polyoxyethylene lauryl ether, polyoxyethylene stearylether and polyoxyethylene oleyl ether; polyoxyethylene alkylphenylethers such as polyoxyethylene octylphenyl ether and polyoxyethylenenonylphenyl ether; polyethylene glycol diesters such as polyethyleneglycol dilaurate and polyethylene glycol distearate; sorbitan fatty acidesters; fatty acid modified polyesters; tertiary amine modifiedpolyurethanes; polyethylene imines; and the like. The surfactant is alsoavailable under the trade name of KP (of Shin-Etsu Chemical Co.),Polyflow (of Kyoeisha Kagaku Kabushiki Kaisha), F-Top (Tokem ProductsCo.), Megafac (Dainippon Ink and Chemicals, Inc.), Florade (Sumitomo 3MLimited), Asahi Guard and Surflon (of Asahi Glass Co.) and the like.

The surfactant listed above can be used alone or in admixture of two ormore.

The amount of the surfactant used is generally 50 parts or less byweight, preferably 0 to 30 parts by weight, based on 100 parts by weightof the total of all pigments.

(B) Alkali-soluble Resin

As the alkali-soluble resin in the present invention, any resin can beused as long as it serves as a binder for the colorant (A) and issoluble in a developer, particularly preferably an alkali developer usedin a development process in the production of a color filter. Thealkali-soluble resin is preferably a carboxyl group-containing polymer,particularly a copolymer (to be simply referred to as “carboxylgroup-containing copolymer” hereinafter) of an ethylenically unsaturatedmonomer having at least one carboxyl group (to be simply referred to as“carboxyl group-containing unsaturated monomer” hereinafter) and othercopolymerizable ethylenically unsaturated monomer (to be simply referredto as “copolymerizable unsaturated monomer” hereinafter).

Illustrative examples of the above carboxyl group-containing unsaturatedmonomer include unsaturated monocarboxylic acids such as acrylic acid,methacrylic acid, crotonic acid, a-chloroacrylic acid and cinammic acid;unsaturated dicarboxylic acids such as maleic acid, maleic anhydride,fumaric acid, itaconic acid, itaconic anhydride, citraconic acid,citraconic anhydride and mesaconic acid, and anhydrides thereof;unsaturated polycarboxylic acids (anhydrides) having a valence of 3 ormore; mono[(meth)acryloyloxyalkyl]esters of polycarboxylic acids havinga valence of 2 or more, such as mono(2-acryloyloxyethyl) succinate,mono(2-methacryloyloxyethyl) succinate,mono(2-acryloyloxyethyl)phathalate and mono(2-methacryloyloxyethyl)phthalate; mono(meth)acrylates of both-terminal dicarboxy polymers suchas ω-carboxy polycaprolactone monoacrylate and ω-carboxypolycaprolactonemonomethacrylate; and the like.

These carboxyl group-containing unsaturated monomers can be used aloneor in admixture of two or more.

Illustrative examples of the copolymerizable unsaturated monomer includearomatic vinyl compounds such as styrene, α-methylstyrene,o-vinyltoluene, m-vinyltoluene, p-vinyltoluene, p-chlorostyrene,o-methoxystyrene, m-methoxystyrene, p-methoxystyrene,o-vinylbenzylmethyl ether, m-vinylbenzylmethyl ether,p-vinylbenzylmethyl ether, o-vinylbenzylglycidyl ether,m-vinylbenzylglycidyl ether, p-vinylbenzylglycidyl ether and indene;unsaturated carboxylic acid esters such as methyl acrylate, methylmethacrylate, ethyl acrylate, ethyl methacrylate, n-propyl acrylate,n-propyl methacrylate, i-propyl acrylate, i-propyl methacrylate, n-butylacrylate, n-butyl methacrylate, i-butyl acrylate, i-butyl methacrylate,sec-butyl acrylate, sec-butyl methacrylate, t-butyl acrylate, t-butylmethacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethyl methacrylate,2-hydroxypropyl acrylate, 2-hydroxypropyl methacrylate, 3-hydroxypropylacrylate, 3-hydroxypropyl methacrylate, 2-hydroxybutyl acrylate,2-hydroxybutyl methacrylate, 3-hydroxybutyl acrylate, 3-hydroxybutylmethacrylate, 4-hydroxybutyl acrylate, 4-hydroxybutyl methacrylate,allyl acrylate, allyl methacrylate, benzyl acrylate, benzylmethacrylate, cyclohexyl acrylate, cyclohexyl methacrylate, phenylacrylate, phenyl methacrylate, 2-methbxyethyl acrylate, 2-methoxyethylmethacrylate, 2-phenoxyethyl acrylate, 2-phenoxyethyl methacrylate,methoxydiethylene glycol acrylate, methoxydiethylene glycolmethacrylate, methoxytriethylene glycol acrylate, methoxytriethyleneglycol methacrylate, methoxypropylene glycol acrylate, methoxypropyleneglycol methacrylate, methoxydipropylene glycol acrylate,methoxydipropylene glycol methacrylate, isobornyl acrylate, isobornylmethacrylate, dicyclopentadienyl acrylate, dicyclopentadienylmethacrylate, 2-hydroxy-3-phenoxypropyl acrylate and2-hydroxy-3-phenoxypropyl methacrylate; unsaturated carboxylic acidaminoalkyl esters such as 2-aminoethyl acrylate, 2-aminoethylmethacrylate, 2-dimethylaminoethyl acrylate, 2-dimethylaminoethylmethacrylate, 2-aminopropyl acrylate, 2-aminopropyl methacrylate,2-dimethylaminopropyl acrylate, 2-dimethylaminopropyl methacrylate,3-aminopropyl acrylate, 3-aminopropyl methacrylate,3-dimethylaminopropyl acrylate and 3-dimethylaminopropyl methacrylate;unsaturated carboxylic acid glycidyl esters such as glycidyl acrylateand glycidyl methacrylate; carboxylic acid vinyl esters such as vinylacetate, vinyl propionate, vinyl butyrate and vinyl benzoate;unsaturated ethers such as vinylmethyl ether, vinylethyl ether andallylglycidyl ether; vinyl cyanide compounds such as acrylonitrile,methacrylonitrile, α-chloroacrylonitrile and vinylidene cyanide;unsaturated amides such as acrylamide, methacrylamide,α-chloroacrylamide, N-2-hydroxyethyl acrylamide and N-2-hydroxyethylmethacrylamlde; unsaturated imides such as maleimide, N-phenyl maleimideand N-cyclohexyl maleimide; aliphatic conjugated dienes such as1,3-butadiene, isoprene and chloroprene; macromonomers having amonoacryloyl group or monomethacryloyl group at the terminal of apolymer molecular chain, such as polystyrene, polymethyl acrylate,polymethyl methacrylate, poly-n-butyl acrylate, poly-n-butylmethacrylate and polysiloxane; and the like.

These copolymerizable unsaturated monomers can be used alone or inadmixture of two or more.

The carboxyl group-containing copolymer in the present invention ispreferably a copolymer (to be referred to as “carboxyl group-containingcopolymer (I)” hereinafter) of (1) a carboxyl group-containingunsaturated monomer component comprising acrylic acid and/or methacrylicacid as an essential component and, in addition,mono(2-acryloyloxyethyl)succinate and/ormono(2-methacryloyloxyethyl)succinate as the case may be and (2) atleast one selected from the group consisting of styrene, methylacrylate, methyl methacrylate, 2-hydroxyethyl acrylate, 2-hydroxyethylmethacrylate, allyl acrylate, allyl methacrylate, benzyl acrylate,benzyl methacrylate, N-phenyl maleimide, polystyrene macromonomer andpolymethyl methacrylate macromonomer.

Illustrative examples of the carboxyl group-containing copolymer (I)include (meth)acrylic acid/methyl (meth)acrylate copolymer;(meth)acrylic acid/benzyl (meth)acrylate copolymer; (meth)acrylicacid/2-hydroxyethyl (meth)acrylate/benzyl (meth)acrylate copolymer;(meth)acrylic acid/methyl (meth)acrylate/polystyrene macromonomercopolymer, (meth)acrylic acid/methyl (meth)acrylate/polymethylmethacrylate macromonomer copolymer; (meth)acrylic acid/benzyl(meth)acrylate/polystyrene macromonomer copolymer; (meth)acrylicacid/benzyl (meth)acrylate/polymethyl methacrylate macromonomercopolymer; (meth)acrylic acid/2-hydroxyethyl (meth)acrylate/benzyl(meth)acrylate/polystyrene macromonomer copolymer; (meth)acrylicacid/2-hydroxyethyl (meth)acrylate/benzyl (meth)acrylate/polymethylmethacrylate macromonomer copolymer; methacrylic acid/styrene/benzylmethacrylate/N-phenyl maleimide copolymer; methacrylicacid/mono(2-acryloyloxyethyl) succinate/styrene/benzylmethacrylate/N-phenyl maleimide copolymer; methacrylicacid/mono(2-acryloyloxyethyl) succinate/styrene/allylmethacrylate/N-phenyl maleimide copolymer; and the like.

The proportion of the carboxyl group-containing unsaturated monomer inthe carboxyl group-containing copolymer is generally 5 to 50 wt %,preferably 10 to 40 wt %. When the proportion is less than 5 wt %, thesolubility of the obtained radiation sensitive composition in an alkalideveloper is liable to lower. On the other hand, when the proportion ismore than 50 wt %, the solubility becomes too high, whereby the formedpixels are liable to fall off from the substrate, or the surface of eachof the pixels is liable to be roughened at the time of development withan alkali developer.

The weight-average molecular weight in terms of polystyrene (to beabbreviated as Mw hereinafter), measured by gel permeationchromatography (GPC, dissolving solvent: tetrahydrofuran), of thealkali-soluble resin in the present invention is generally 3,000 to300,000, preferably 5,000 to 100,000. Using an alkali-soluble resinhaving the Mw in the above specific range, a radiation sensitivecomposition having excellent developability can be obtained, wherebypixels having a sharp pattern edge can be formed and stains and filmresidues are hardly produced in an area other than a portion wherepixels are formed on the substrate at the time of development.

In the present invention, alkali-soluble resins can be used alone or inadmixture of two or more.

The amount of the alkali-soluble resin used in the present invention isgenerally 10 to 1,000 parts by weight, preferably 20 to 500 parts byweight, based on 100 parts by weight of the colorant (A). When theamount of the alkali-soluble resin used is less than 10 parts by weight,for example, alkali developability may deteriorate, and stains and filmresidues are liable to be produced in an area other than a portion wherepixels are formed on the substrate. On the other hand, when the amountis more than 1,000 parts by weight, it may be difficult to achieve acolor density required for a color filter due to a relative reduction inthe concentration of the pigment.

(C) Polyfunctional Monomer

The polyfunctional monomer in the present invention is a monomer havingtwo or more polymerizable unsaturated bonds.

Illustrative examples of the polyfunctional monomer include diacrylatesand dimethacrylates of alkylene glycol such as ethylene glycol andpropylene glycol; diacrylates and dimethacrylates of polyalkylene glycolsuch as polyethylene glycol and polypropylene glycol; polyacrylates andpolymethacrylates of polyhydric alcohols having a valence of 3 or moresuch as glycerine, trimethylolpropane, pentaerythritol anddipentaerythritol, and dicarboxylic acid modified products thereof;oligoacrylates and oligomethacrylates such as polyesters, epoxy resins,urethane resins, alkyd resins, silicone resins and spiran resins;diacrylates and dimethacrylates of both terminal hydroxylated polymerssuch as both terminal hydroxypoly-1,3-butadiene, both terminalhydroxypolyisoprene and both terminal hydroxypolycaprolactone;tris(2-acryloyloxyethyl)phosphate, tris(2-methacryloyloxyethyl)phosphateand the like.

Out of these polyfunctional monomers, preferred are polyacrylates andpolymethacrylates of polyhydric alcohols having a valence of 3 or moreand dicarboxylic acid modified products thereof, such astrimethylolpropane triacrylate, trimethylolpropane trimethacrylate,pentaerythritol triacrylate, pentaerythritol trimethacrylate,pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate,dipentaerythritol pentaacrylate, dipentaerythritol pentamethacrylate,dipentaerythritol hexaacrylate, dipentaerythritol hexamethacrylate, andcompounds represented by the following formula (2), and particularlypreferred are trimethylolpropane triacrylate, pentaerythritoltriacrylate and dipentaerythritol hexaacrylate because they have a highpixel strength and an excellent smooth pixel surface and hardly producestains or film residues in an area other than a portion where pixels areformed.

The above polyfunctional monomers can be used alone or in admixture oftwo or more.

The amount of the polyfunctional monomer used in the present inventionis generally 5 to 500 parts by weight, preferably 20 to 300 parts byweight, based on 100 parts by weight of the alkali-soluble resin (B).When the amount of the polyfunctional monomer used is less than 5 partsby weight, the strength and surface smoothness of the obtained pixel maydeteriorate. On the other hand, when the amount is more than 500 partsby weight, alkali developability may lower, and stains or film residuesare liable to be produced in an area other than a portion where pixelsare formed on the substrate.

In the present invention, a monofunctional monomer can be used incombination with the above polyfunctional monomer as required.

Illustrative examples of the monofunctional monomer include carboxylgroup-containing unsaturated monomers and copolymerizable unsaturatedmonomers listed for the above carboxyl group-containing copolymer,M-5300 (trade name, manufactured by Toagosei Chemical Industry Co.,Ltd.) and the like.

These monofunctional monomers can be used alone or in admixture of twoor more.

The proportion of the monofunctional monomer used is generally 90 wt %or less, preferably 0 to 50 wt %, based on the total of thepolyfunctional monomer and the monofunctional monomer. When theproportion is more than 90 wt %, the strength and surface smoothness ofthe obtained pixel may be insufficient.

(D) Photopolymerization Initiator

The term “photopolymerization initiator” as used in the presentinvention refers to a compound which causes decomposition or thecleavage of a bond and forms an active species capable of initiating thepolymerization of the above polyfunctional monomer (C), such as aradical, cation or anion, when exposed to radiation such as visiblelight, ultraviolet light, far ultraviolet light, electron beam or X-ray(to be referred to as “exposure” hereinafter).

Illustrative examples of the photopolymerization initiator includeimidazole-based compounds having at least one main skeleton representedby the following formulas (3), (4) or (5), benzoin-based compounds,acetophenone-based compounds, benzophenone-based compounds,α-diketone-based compounds, polynuclear quinone-based compounds,xanthone-based compounds, diazo-based compounds, triazine-basedcompounds and the like.

The imidazole-based compounds include, for example,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-blimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-blimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-bromophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-bromophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-bromophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-tribromophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-tribromophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4,6-tribromophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-cyanophenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-cyanophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-cyanophenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-methylphenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-methylphenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-methylphenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-ethylphenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-ethylphenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-ethylphenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-phenylphenyl)-4,4′,5,5′-tetrakis(4-methoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-phenylphenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-phenylphenyl)-4,4′,5,5′-tetrakis(4-phenoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-bromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-tribromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-cyanophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dicyanophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-tricyanophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-methylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dimethylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-trimethylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-ethylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-diethylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-triethylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2-phenylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-diphenylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-triphenylphenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,and the like.

Out of these -biimidazole-based compounds, particularly preferred are2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2-bromophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole and2,2′-bis(2,4,6-tribromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole.

The above biimidazole-based compounds have excellent solubility in asolvent, do not produce foreign matters such as undissolved substance ordeposits, are very sensitive, promote a curing reaction thoroughly byexposure with a small amount of energy, give high contrast, and do notcause a curing reaction in unexposed portions. Therefore, the coatingfilm after exposure is clearly divided into cured portions insoluble ina developer and uncured portions highly soluble in the developer,whereby an undercutless pixel pattern can be obtained and an array ofhigh-definition pixels arranged according to a predetermined pattern canbe formed.

The above benzoin-based compounds include, for example, benzoin, benzoinmethyl ether, benzoin ethyl ether, benzoin i-propyl ether, benzoini-butyl ether, methyl-2-benzoyl benzoate and the like.

The above acetophenone-based compounds include, for example,2,2-dimethoxy-2-phenylacetophenone,2-hydroxy-2-methyl-1-phenylpropane-1-one,1-(4-i-propylphenyl)-2-hydroxy-2-methylpropane-1-one,4-(2-hydroxyethoxy)phenyl-(2-hydroxy-2-propyl)ketone,2,2-dimethoxyacetophenone, 2,2-diethoxyacetophenone,2-methyl-(4-methylthiophenyl)-2-morpholino-1-propane-1-one,2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one,1-hydroxycyclohexylphenyl ketone,2,2′-dimethoxy-1,2-diphenylethane-1-one, 4-azidoacetophenone,4-azidobenzalacetophenone and the like.

The above benzophenone-based compounds include, for example,benzophenone, 4,4′-bis(dimethylamino)benzophenone,4,4′-bis(dlethylamino)benzophenone, 3,3′-dimethyl-4-methoxybenzophenoneand the like.

The α-diketone-based compounds include, for example, diacetyl,dibenzoyl, methylbenzoyl formate and the like.

The above polynuclear quinone-based compounds include, for example,anthraquinone, 2-ethylanthraquinone, 2-t-butylanthraquinone,1,4-naphthoquinone and the like.

The above xanthone-based compounds include, for example, xanthone,thioxanthone, 2,4-diethylthioxanthone, 2-chlorothioxanthone and thelike.

The above diazo-based compounds include, for example,4-diazodiphenylamine, 4-diazo-4′-methoxydiphenylamine,4-diazo-3-methoxydiphenylamine and the like.

The above triazine-based compounds include, for example,2-(2′-furylethylidene)-4,6-bis(trichloromethyl)-s-triazine,2-(3′,4′-dimethoxystyryl)-4,6-bis(trichloromethyl)-s-triazine,2-(4′-methoxynaphthyl)-4,6-bis(trichloromethyl)-s-triazine,2-(2′-bromo-4′-methylphenyl)-4,6-bis(trichloromethyl)-s-triazine,2-(2′-thiophenylethylidene)-4,6-bis(trichloromethyl)-s-triazine and thelike.

Photopolymerization initiators other than the above photopolymerizationinitiators include 4-azidobenzaldehyde, azidopyrene,bis(2,6-dimethoxybenzoyl)-2,4,4-trimethylpentylphosphine oxide,N-phenylthioacridone, triphenylpyrylium perchlorate and the like.

The photopolymerization initiator listed above can be used alone or inadmixture of two or more.

The amount of the photopolymerization initiator used in the presentinvention is generally 0.01 to 200 parts by weight, preferably 1 to 120parts by weight, particularly preferably 1 to 50 parts by weight, basedon 100 parts by weight of the total of the polyfunctional monomer (C)and the monofunctional monomer which is used as the case may be. Whenthe amount of the photopolymerization initiator is less than 0.01 partby weight, curing by exposure may be insufficient, thereby making itdifficult to obtain an array of pixels arranged according to apredetermined pattern. On the other hand, when the amount is more than200 parts by weight, the formed pixels easily fall off from thesubstrate at the time of development, and stains or film residues areeasily produced in an area other than a portion where the pixels areformed on the substrate.

Further, in the present invention, at least one of a sensitizer, curingpromoting agent and polymer photocrosslinking sensitizing agent (to begenerally and inclusively referred to as “curing aids” hereinafter) canbe used in conjunction with the above photopolymerization initiator asrequired.

Illustrative examples of the sensitizer include4-diethylaminoacetophenone, 4-dimethylaminopropiophenone,ethyl-4-dimethylaminobenzoate, 2-ethylhexyl-1,4-dimethylaminobenzoate,2,5-bis(4′-diethylaminobenzal)cyclohexanone,7-diethylamino-3-(4-diethylaminobenzoyl)coumarin,4-(diethylamino)chalcone and the like.

The sensitizer listed above can be used alone or in admixture of two ormore.

Illustrative examples of the curing promoting agent include chaintransfer agents such as 2-mercaptobenzoimidazole,2-mercaptobenzothiazole, 2-mercaptobenzooxazole,2,5-dimercapto-1,3,4-thiadiazole, 2-mercapto-4,6-dimethylaminopyridine,1-phenyl-5-mercapto-1H-tetrazole and3-mercapto-4-methyl-4H-1,2,4-triazole and the like.

The curing promoting agent listed above can be used alone or inadmixture of two or more.

The above polymer photocrosslinking-sensitizing agent is a polymercompound which has at least one functional group in the main chainand/or side chain and which can serve as a crosslinking agent and/orsensitizer when exposed to radiation. Illustrative examples of thephotocrosslinking-sensitizing agent include condensates of4-azidobenzaldehyde and polyvinyl alcohols, condensates of4-azidobenzaldehyde and phenolic novolak resins, homopolymers andcopolymers of 4-acryloylphenylcinnamoyl esters, 1,4-polybutadiene,1,2-polybutadiene and the like.

The polymer photocrosslinking sensitizing agent listed above can be usedalone or in admixture of two or more.

The amount of the curing aids used is generally 300 parts or less byweight, preferably 5 to 200 parts by weight, more preferably 10 to 100parts by weight, based on 100 parts by weight of the photopolymerizationinitiator (D).

In the present invention, a combination of a biimidazole-based compoundand a benzophenone-based compound as a photopolymerization initiatorand/or a thiazole-based curing promoting agent is particularlypreferably used because the formed pixels rarely fall off from thesubstrate at the time of development and the strength and sensitivity ofthe pixels are high.

In the present invention, when a combination of a biimidazole-basedcompound and another component is used as a photopolymerizationinitiator, the proportion of the another component is preferably 80 wt %or less, based on the total weight of the photopolymerization initiator.

Particularly preferred combinations of constituent components of thephotopolymerization initiator are2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/1-hydroxycyclohexylphenylketone,2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetrakis(4-ethoxycarbonylphenyl)-1,2′-biimidazole/4,4′-bis(dimethylamino)benzophenone/1-hydroxycyclohexylphenylketone/2-mercaptobenzothiazole,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one,2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one/2-mercaptobenzothiazole,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/2-benzyl-2-dimethylamino-1-(4-morpholinophenyl)butane-1-one,2,2′-bis(2,4-dibromophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(diethylamino)benzophenone/1-hydroxycyclohexylphenylketone, and2,2′-bis(2,4,6-trichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole/4,4′-bis(dimethylamino)benzophenone/1-hydroxycyclohexylphenylketone/2-mercaptobenzothiazole.

Other Additives

The radiation sensitive composition of the present invention can containan organic acid to improve its solubility in an alkali developer and tofurther suppress the generation of undissolved substance afterdevelopment.

The organic acid is preferably an aliphatic carboxylic acid and phenylgroup-containing carboxylic acid having a molecular weight of 1,000 orless.

Illustrative examples of the aliphatic carboxylic acid includemonocarboxylic acids such as formic acid, acetic acid, propionic acid,butyric acid, valeric acid, pivalic acid, caproic acid, diethylaceticacid, enanthic acid and caprylic acid; dicarboxylic acids such as oxalicacid, malonic acid, succinic acid, glutaric acid, adipic acid, pimelicacid, suberic acid, azelaic acid, sebacic acid, brassylic acid,methylmalonic acid, ethylmalonic acid, dimethylmalonic acid,methylsuccinic acid, tetramethylsuccinic acid, cyclohexanedicarboxylicacid, itaconic acid, citraconic acid, maleic acid, fumaric acid andmesaconic acid; tricarboxylic acids such as tricarballylic acid,aconitic acid and camphoronic acid; and the like.

The phenyl group-containing carboxylic acid is an aromatic carboxylicacid having a carboxyl group directly bonded to a phenyl group or acarboxylic acid having a carboxyl group bonded to a phenyl group througha carbon chain.

Illustrative examples of the phenyl group-containing carboxylic acidinclude aromatic monocarboxylic acids such as benzoic acid, toluic acid,cuminic acid, hemellitic acid and mesitylenic acid; aromaticdicarboxylic acids such as phthalic acid, isophthalic acid andterephthalic acid; aromatic polycarboxylic acids having a valence of 3or more such as trimellitic acid, trimesic acid, mellophanic acid andpyromellitic acid; phenylacetic acid; hydroatropic acid; hydrocinnamicacid; mandelic acid; phenylsuccinic acid; atropic acid; cinnamic acid;cinnamylidenic acid; coumaric acid; umbellic acid; and the like.

Out of these organic acids, aliphatic dicarboxylic acids and aromaticdicarboxylic acids such as malonic acid, adipic acid, itaconic acid,citraconic acid, fumaric acid, mesaconic acid and phthalic acid arepreferred in view of alkali solubility, solubility in a solvent and theprevention of stains and film residues in an area other than a portionwhere pixels are formed on the substrate.

The above organic acid listed above can be used alone or in admixture oftwo or more.

The proportion of the organic acid used is generally 10 wt % or less,preferably 5 wt % or less, more preferably 1 wt % or less, based on theradiation sensitive composition. When the proportion of the organic acidis more than 10 wt %, the adhesion of the formed pixels to the substrateis liable to deteriorate.

The radiation sensitive composition of the present invention can furthercontain various additives other than the above organic acids.

Such additives include, for example, dispersion aids such as bluepigment derivatives and yellow pigment derivatives exemplified by copperphthalocyanine derivatives; fillers such as glass and alumina; polymercompounds such as polyvinyl alcohols, polyethylene glycol monoalkylethers and poly(chloroalkylacrylates); adhesion promoting agents such asvinyltrimethoxysilane, vinyltriethoxysilane,vinyltris(2-methoxyethoxy)silane,N-(2-aminoethyl)-3-aminopropylmethyldimethoxysilane,N-(2-aminoethyl)-3-aminopropyltrimethoxysilane,3-aminopropyltriethoxysilane, 3-glycidoxypropyltrimethoxysilane,3-glycidylpropyltrimethoxysilane,3-glycidoxypropylmethyldimethoxysilane,2-(3,4-epoxycyclohexyl)ethyltrimethoxysilane,3-chloropropylmethyldimethoxysilane, 3-chloropropyltrimethoxysilane,3-methacryloxypropyltrimethoxysilane and3-mercaptopropyltrimethoxysilane; antioxidants such as2,2-thiobis(4-methyl-6-t-butylphenol) and 2,6-di-t-butylphenol;ultraviolet absorbers such as2-(3-t-butyl-5-methyl-2-hydroxyphenyl)-5-chlorobenzotriazole andalkoxybenzophenone; agglomeration prevention agents such as sodiumpolyacrylates; heat crosslinking agents such as epoxy compounds,melamine compounds and bisazido compounds; the like.

Solvent

The radiation sensitive composition of the present invention comprisesthe above components (A) to (D) as essential ingredients and otheradditives as the case may be, and is generally prepared as a liquidcomposition by adding a solvent.

Any solvent is acceptable as the above solvent, as long as it dissolvesor disperses the above components constituting the radiation sensitivecomposition, does not react with these components and exhibitsappropriate volatility.

Illustrative examples of the solvent include (poly)alkylene glycolmonoalkyl ethers such as ethylene glycol monomethyl ether, ethyleneglycol monoethyl ether, ethylene glycol mono-n-propyl ether, ethyleneglycol mono-n-butyl ether, diethylene glycol monomethyl ether,diethylene glycol monoethyl ether, diethylene glycol mono-n-propylether, diethylene glycol mono-n-butyl ether, triethylene glycolmonomethyl ether, triethylene glycol monoethyl ether, propylene glycolmonomethyl ether, propylene glycol monoethyl ether, propylene glycolmono-n-propyl ether, propylene glycol mono-n-butyl ether, dipropylieneglycol monomethyl ether, dipropylene glycol monoethyl ether, dipropyleneglycol mono-n-propyl ether, dipropylene glycol mono-n-butyl ether,tripropylene glycol monomethyl ether and tripropylene glycol monoethylether; (poly)alkylene glycol monoalkyl ether acetates such as ethyleneglycol monomethyl ether acetate, ethylene glycol monoethyl etheracetate, propylene glycol monomethyl ether acetate and propylene glycolmonoethyl ether acetate; other ethers such as diethylene glycol dimethylether, diethylene glycol methylethyl ether, diethylene glycol diethylether and tetrahydrofuran; ketones such as methyl ethyl ketone,cyclohexanone, 2-heptanone and 3-heptanone; lactic acid alkyl esterssuch as methyl 2-hydroxypropionic acid and ethyl 2-hydroxypropionicacid; other esters such as ethyl 2-hydroxy-2-methylpropionic acid,methyl 3-methoxypropionic acid, ethyl 3-methoxypropionic acid, methyl3-ethoxypropionic acid, ethyl 3-ethoxypropionic acid, ethyl ethoxyaceticacid, ethyl hydroxyacetic acid, methyl 2-hydroxy-3-methylbutanoic acid,3-methyl-3-methoxybutyl acetate, 3-methyl-3-methoxybutyl propionate,ethyl acetate, n-butyl acetate, i-butyl acetate, n-amyl formate, i-amylacetate, n-butyl propionate, i-propyl butyrate, ethyl butyrate, n-butylbutyrate, methylpyruvic acid, ethylpyruvic acid, n-propylpyruvic acid,methyl acetoacetate, ethyl acetoacetate and ethyl 2-oxobutanoic acid;aromatic hydrocarbons such as toluene and xylene; amides such asN-methylpyrrolidone, N,N-dimethylformamide and N,N-dimethylacetoamide;and the like.

Of these, ethylene glycol monomethyl ether acetate, propylene glycolmonomethyl ether, propylene glycol monomethyl ether acetate, propyleneglycol monoethyl ether acetate, diethylene glycol dimethyl ether,diethylene glycol methylethyl ether, cyclohexanone, 2-heptanone,3-heptanone, ethyl 2-hydroxypropionic acid, 3-methyl-3-methoxybutylpropionate, ethyl 3-methoxypropionic acid, methyl 3-ethoxypropionicacid, ethyl 3-ethoxypropionic acid, n-butyl acetate, i-butyl acetate,n-amyl formate, i-amyl acetate, n-butyl propionate, ethyl butyrate,i-propyl butyrate, n-butyl butyrate and ethylpyruvic acid are preferredin view of solubility, pigment dispersibility and applicationproperties.

The solvent listed above can be used alone or in admixture of two ormore.

The solvent can be used in conjunction with a high-boiling solvent suchas benzylethyl ether, dihexyl ether, acetonylacetone, isophorone,caproic acid, caprylic acid, 1-octanol, 1-nonanol, benzyl alcohol,benzyl acetate, ethyl benzoate, diethyl oxalate, diethyl maleate,γ-butyrolactone, ethylene carbonate, propylene carbonate or phenylcellosolve acetate.

Out of the above high-boiling solvents, γ-butyrolactone is preferred.

The high-boiling solvent listed above can be used alone or in admixtureof two or more.

The proportion of the solvent is not particularly limited, but it isdesirably contained in such an amount that the total concentration ofthe components, excluding the solvent, contained in the composition isto be generally 5 to 50 wt %, preferably 10 to 40 wt %, in view of theapplication properties and stability of the obtained radiation sensitivecomposition.

The following examples are provided for the purpose of furtherillustrating the present invention, while the present invention shallnot be limited thereto.

EXAMPLE 1

100 parts by weight of a mixture of C.I. Pigment Violet 19 and C.I.Pigment Orange 71 in a weight ratio of 75/25 as the colorant (A1), 60parts by weight of a methacrylic acid/2-hydroxyethyl methacrylate/benzylmethacrylate copolymer (weight ratio=15/15/70, Mw=28,000) as thealkali-soluble resin (B), 40 parts by weight of dipentaerythritolhexaacrylate as the polyfunctional monomer (C), 10 parts by weight of2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole and10 parts by weight of 4,4′-bis(diethylamino)benzophenone as thephotopolymerization initiator (D), and 1,000 parts by weight of ethyl3-ethoxypropionic acid as a solvent were mixed together to prepare aliquid radiation sensitive composition (composition 1).

[Production of Color Filter]

A red striped color filter was produced on a transparent substrate usingthe above liquid composition as follows.

The liquid composition was applied to the surface of a soda glasssubstrate having an SiO₂ film formed thereon for preventing thedissolution of sodium ions using a spin coater, and the resultingsubstrate was prebaked in a clean oven heated at 80° C. for 10 minutesto form a 0.8-μm-thick coating film.

Thereafter, the substrate was cooled to room temperature and exposed toultraviolet light having a wavelength of 365 nm, 405 nm and 436 nm witha dosage of 200 mJ/cm² through a photomask using a high-pressure mercurylamp. This substrate was then immersed in a 0.04-wt % aqueous solutionof potassium hydroxide heated at 23° C. for 1 minute for development,washed with super purified water and dried. Thereafter, the substratewas post-baked in the clean oven heated at 230° C. for 30 minutes toproduce a red striped color filter on the soda glass substrate.

[Evaluation of Color Filter]

The obtained color filter was evaluated as follows.

Heat Resistance

The chromaticity (α) of the color filter right after its production andthe chromaticity (β) of the color filter after 1 hour of heating at 250°C. were measured with a microanalyzer (TC-1800M of Tokyo Denshoku Co.,Ltd.). The heat resistance of the color filter was evaluated based onthe difference (ΔEab) between the chromaticity (β) and the chromaticity(α). ΔEab was 1.75.

Light Resistance

The color filter produced in the same manner as described above wasexposed to ultraviolet light using a ultraviolet long-life fade meter(of Suga Shikenki Co., Ltd.) to measure the chromaticity (γ) of thecolor filter after 90 hours of exposure using a microanalyzer (TC-1800Mof Tokyo Denshoku Co., Ltd.). The light resistance of the color filterwas evaluated based on the difference (ΔEab) of the chromaticity (γ) andthe chromaticity (α) of the color filter right after its production. Asa result, ΔEab was 1.85.

Spectral Transmittance

The spectral transmittance of the color filter was measured using amicroanalyzer (TC-1800M of Tokyo Denshoku Co., Ltd.). The measurementresult is shown in FIG. 1. This color filter had a high spectraltransmittance at a wavelength of 500 nm or less and a wavelength of 610nm.

Comparative Example 1

A liquid composition was prepared and a color filter was produced andevaluated in the same manner as in Example 1 except that 100 parts byweight of a mixture of C.I. Pigment Red 177 and C.I. Pigment Violet 23in a weight ratio of 70/30 were used as the colorant (A).

As a result, this color filter had ΔEab of 2.10 for heat resistance andΔEab of 2.31 for light resistance, which were insufficient. Themeasurement result of the spectral transmittance of this color filter isshown in FIG. 2. This color filter had a low spectral transmittance at awavelength of 500 nm or less and a wavelength of 610 nm.

Comparative Example 2

A liquid composition was prepared and a color filter was produced andevaluated in the same manner as in Example 1 except that 100 parts byweight of a mixture of C.I. Pigment Red 177 and C.I. Pigment Yellow 83in a weight ratio of 90/10 were used as the colorant (A).

As a result, this color filter had ΔEab of 2.05 for heat resistance andΔEab of 2.12 for light resistance, which were insufficient. Themeasurement result of the spectral transmittance of this color filter isshown in FIG. 3. This color filter had a low spectral transmittanceespecially at a wavelength of 500 nm or less.

EXAMPLE 2

100 parts by weight of a mixture of C.I. Pigment Yellow 110 and C.I.Pigment Yellow 83 in a weight ratio of 85/15 as the colorant (A2), 60parts by weight of a methacrylic acid/benzyl methacrylate/2-hydroxyethylmethacrylate copolymer (weight ratio=15/70/15, Mw=28,000) as thealkali-soluble resin (B), 40 parts by weight of dipentaerythritolhexaacrylate as the polyfunctional monomer (C), 10 parts by weight of2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenyl-1,2′-biimidazole and10 parts by weight of 4,4′-bis(diethylamino)benzophenone as thephotopolymerization initiator (D), and 1,000 parts by weight of ethyl3-ethoxypropionic acid as a solvent were mixed together to prepare aliquid radiation sensitive composition (composition 2).

[Production of Color Filter]

A yellow striped color filter was produced on a transparent substrateusing the composition (2) in the same manner as in Example 1.

[Evaluation of Color Filter]

The obtained color filter was evaluated as follows.

Heat Resistance

The heat resistance of the color filter was evaluated in the same manneras in Example 1. As a result, ΔEab was 1.56.

Light Resistance

The light resistance of the color filter was evaluated in the samemanner as in Example 1. As a result, ΔEab was 2.05.

Spectral Transmittance

The spectral transmittance of the color filter was measured in the samemanner was in Example 1. The measurement result is shown in FIG. 4(solid line). The spectral transmittance of this color filter isslightly lower than the spectral transmittance (dotted line) ofComparative Example 3, though it is still high.

Comparative Example 3

A liquid radiation sensitive composition was prepared and a color filterwas produced and evaluated in the same manner as in Example 1 exceptthat C.I. Pigment Yellow 110 was used alone in place of the mixture ofC.I. Pigment Yellow 110 and C.I. Pigment Yellow 83 as the colorant (A).

As a result, this color filter had ΔEab of 1.65 for heat resistance andΔEab of 2.15 for light resistance, which were unsatisfactory. Themeasurement result of the spectral transmittance of this color filter isshown in FIG. 4 (dotted line).

EXAMPLE 3

100 parts by weight of a mixture of C.I. Pigment Blue 15:4 and C.I.Pigment Green 7 in a weight ratio of 60/40 as the colorant (A3), 60parts by weight of a methacrylic acid/benzyl methacrylate/2-hydroxyethylmethacrylate copolymer (weight ratio=15/70/15, Mw=28,000) as thealkali-soluble resin (B), 40 parts by weight of dipentaerythritolhexaacrylate as the polyfunctional monomer (C), 10 parts by weight of2,2′-bis(2,4-dichlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole and 10parts by weight of 4,4′-bis(diethylamino)benzophenone as thephotopolymerization initiator (D), and 1,000 parts by weight of ethyl3-ethoxypropionic acid as a solvent were mixed together to prepare aliquid radiation sensitive composition (composition 3).

[Production of Color Filter]

A cyanic striped color filter was produced on a transparent substrateusing the above liquid composition in the same manner as in Example 1.

[Evaluation of Color Filter]

The obtained color filter was evaluated as follows.

Heat Resistance

The heat resistance of the color filter was evaluated in the same manneras in Example 1. As a result, ΔEab was 2.65.

Light Resistance

The light resistance of the color filter was evaluated in the samemanner as in Example 1. As a result, ΔEab was 2.45.

Spectral Transmittance

The spectral transmittance of the color filter was measured in the samemanner as in Example 1. The measurement result is shown in FIG. 5.

EXAMPLE 4

A liquid composition (composition 4) was prepared and a color filter wasproduced and evaluated in the same manner as in Example 3 except that100 parts by weight of a mixture of C.I. Pigment Blue 15:4 and C.I.Pigment Green 36 in a weight ratio of 70/30 were used as the colorant(A).

As a result, this color filter had ΔEab of 2.85 for heat resistance andΔEab of 2.57 for light resistance. The measurement result of thespectral transmittance of this color filter is shown in FIG. 6.

Comparative Example 4

A liquid composition was prepared and a color filter was produced andevaluated in the same manner as in Example 3 except that 100 parts byweight of a mixture of C.I. Pigment Blue 15:4 and C.I. Pigment Yellow138 in a weight ratio of 85/15 were used as the colorant (A).

As a result, this color filter had ΔEab of 3.25 for heat resistance andΔEab of 3.07 for light resistance. The measurement result of thespectral transmittance of this color filter is shown in FIG. 7.

EXAMPLE 5

100 parts by weight of C.I. Pigment Red 122 as the organic pigment (A),60 parts by weight of a methacrylic acid/benzylmethacrylate/2-hydroxyethyl methacrylate copolymer (weightratio=15/75/15, Mw=28,000) as the alkali-soluble resin (B), 40 parts byweight of dipentaerythritol hexaacrylate as the polyfunctional monomer(C), 10 parts by weight of2,2′-bis(2-chlorophenyl)-4,4′,5,5′-tetraphenylbiimidazole and 10 partsby weight of 4,4′-bis(diethylamino)benzophenone as thephotopolymerization initiator (D), and 1,000 parts by weight of ethyl3-ethoxypropionic acid as a solvent were mixed together to prepare aliquid radiation sensitive composition (composition 5).

Reference Example 1

A liquid radiation sensitive composition (Y1) was prepared in the samemanner as in Example 1 except that C.I. Pigment Yellow 110/C.I. PigmentYellow 83 were used in place of C.I. Pigment Red 122.

Reference Example 2

A liquid radiation sensitive composition (C1) was prepared in the samemanner as in Example 1 except that a cyanogen pigment (C.I. Pigment Blue15:4/C.I. Pigment green 36) was used in place of C.I. Pigment Red 122.

[Production of Color Filter]

A color filter was produced by forming red, yellow and cyanic pixelarrays on a transparent substrate using the composition 5, thecomposition (Y1) and the composition (C1) as follows.

The composition 5 was first applied to the surface of a soda glasssubstrate having a SiO₂ film formed thereon for preventing thedissolution of sodium ions using a spin coater and the resultingsubstrate was prebaked in a clean oven heated at 80° C. for 10 minutesto form a 0.8-μm-thick coating film.

Thereafter, the substrate was cooled to room temperature and exposed toultraviolet light having a wavelength of 365 nm, 405 nm and 436 nm witha dosage of 200 mJ/cm² through a photomask using a high-pressure mercurylamp. This substrate was then immersed in a 0.04-wt % aqueous solutionof potassium hydroxide for 1 minute for development, washed with superpurified water and dried. Thereafter, the substrate was post-baked inthe clean oven heated at 230° C. for 30 minutes to form a pixel arrayhaving a 20 μm×20 μm red pixel pattern on the substrate.

Thereafter, the above step of forming the red pixel array was repeatedon the substrate having the red pixel array formed thereon using thecomposition (Y1) and the composition (Cl) to form a pixel array having a20 μm×20 μm yellow pixel pattern and a pixel array having a 20 μm×20 μmcyanic pixel pattern sequentially. Thus, a subtractive color filterhaving three layers of red, yellow and cyanic pixel arrays was produced.

[Evaluation of Color Filter]

The obtained color filter was evaluated as follows.

Heat Resistance

The heat resistance of the color filter was evaluated in the same manneras in Example 1. As a result, ΔEab was 1.26.

Light Resistance

The light resistance of the color filter was evaluated in the samemanner as in Example 1. As a result, ΔEab was 1.95.

White Balance

The above step of forming the red pixel pattern was repeated on thecolor filter produced in the same manner as described above using thecomposition (Y1) or the composition (C1) to form a pixel array having a20 μm×20 μm yellow pixel pattern or a pixel array having a 20 μm×20 μmcyanic pixel pattern. The spectral transmittance of each color filterwas measured using a microanalyzer (TC-1800M of Tokyo Denshoku Co.,Ltd.) to carry out white balance simulation. The result is shown in FIG.8.

Comparative Example 5

A liquid radiation sensitive composition having a red pigment dispersedtherein was prepared in the same manner as in Example 1 except that C.I.Pigment Red 254 was used in place of C.I. Pigment Red 122 as an organicpigment. This liquid composition is designated as composition (r1).

A color filter was produced using the composition (r1), the composition(Y1) and the composition (C1) and evaluated in the same manner asdescribed above.

As a result, this color filter had ΔEab of 1.54 for heat resistance andΔEab of 2.15 for light resistance. The white balance simulation resultof this color filter is shown in FIG. 9.

As described above, the radiation sensitive composition of the presentinvention is excellent in heat resistance and light resistance, hasspectral transmittance optimized based on the spectrum of surroundinglight or excellent white balance, and can provide an additive orsubtractive color filter which is the most suitable for use in areflection-type color liquid crystal display device.

What is claimed is:
 1. A radiation sensitive composition comprising:(A2) a colorant containing a mixture of an isoindolinone pigmentrepresented by the following formula (2)

 and a yellow organic pigment; (B) an alkali-soluble resin; (C) apolyfunctional monomer; and (D) a photopolymerization initiator.
 2. Theradiation sensitive composition of claim 1, wherein the yellow organicpigment is selected from the group consisting of C.I. Pigment Yellow 1,C.I. Pigment Yellow 3, C.I. Pigment Yellow 12, C.I. Pigment Yellow 13,C.I. Pigment Yellow 14, C.I. Pigment Yellow 16, C.I. Pigment Yellow 17,C.I. Pigment Yellow 20, C.I. Pigment Yellow 24, C.I. Pigment Yellow 31,C.I. Pigment Yellow 55, C.I. Pigment Yellow 60, C.I. Pigment Yellow 65,C.I. Pigment Yellow 73, C.I. Pigment Yellow 74, C.I. Pigment Yellow 81,C.I. Pigment Yellow 83, C.I. Pigment Yellow 93, C.I. Pigment Yellow 95,C.I. Pigment Yellow 97, C.I. Pigment Yellow 98, C.I. Pigment Yellow 100,C.I. Pigment Yellow 101, C.I. Pigment Yellow 104, C.I. Pigment Yellow106, C.I. Pigment Yellow 108, C.I. Pigment Yellow 109, C.I. PigmentYellow 113, C.I. Pigment Yellow 114, C.I. Pigment Yellow 116, C.I.Pigment Yellow 117, C.I. Pigment Yellow 119, C.I. Pigment Yellow 120,C.I. Pigment Yellow 126, C.I. Pigment Yellow 127, C.I. Pigment Yellow128, C.I. Pigment Yellow 129, C.I. Pigment Yellow 138, C.I. PigmentYellow 139, C.I. Pigment Yellow 150, C.I. Pigment Yellow 151, C.I.Pigment Yellow 152, C.I. Pigment Yellow 153, C.I. Pigment Yellow 154,C.I. Pigment Yellow 155, C.I. Pigment Yellow 156, C.I. Pigment Yellow166, C.I. Pigment Yellow 168 and C.I. Pigment Yellow
 175. 3. Theradiation sensitive composition of claim 1, wherein the yellow organicpigment is contained in an amount of 25 wt % or less, based on the totalweight of the isoindolinone pigment and the yellow organic pigment. 4.The radiation sensitive composition of claim 1, wherein thealkali-soluble resin (B) is a copolymer of an ethylenically unsaturatedmonomer having at least one carboxyl group and a copolymerizableunsaturated monomer having no carboxyl group.
 5. The radiation sensitivecomposition of claim 4, wherein the ethylenically unsaturated monomerhaving at least one carboxyl group is copolymerized in an amount of 5 to50 wt %, based on the copolymer.
 6. The radiation sensitive compositionof claim 1, wherein the alkali-soluble resin (B) has a weight averagemolecular weight, in terms of polystyrene, of 3,000 to 300,000.
 7. Theradiation sensitive composition of claim 1, wherein the alkali-solubleresin (B) is contained in an amount of 10 to 1,000 parts by weight,based on 100 parts by weight of the colorant.
 8. The radiation sensitivecomposition of claim 1, wherein the polyfunctional monomer (C) iscontained in an amount of 5 to 500 parts by weight, based on 100 partsby weight of the alkali-soluble resin.
 9. The radiation sensitivecomposition of claim 1, wherein the photopolymerization initiator (D) isselected from the group consisting of imidazole compounds, benzoincompounds, acetophenone compounds, benzophenone compounds, α-diketonecompounds, polynuclear quinone compounds, xanthone compounds, diazocompounds and triazine compounds.
 10. The radiation sensitivecomposition of claim 1, wherein the photopolymerization initiator (D) iscontained in an amount of 0.01 to 200 parts by weight, based on 100parts by weight of the polyfunctional monomer (C).